Electrical components are conventionally grounded to painted surfaces of an electrically conducting support structure (e.g., an automobile body) by forming a hole in a selected portion of the support structure, and then attaching a lead wire from the electrical component to be grounded by means of a screw and lug assembly which cooperates with the hole. Attachment of a lead wire to an electrically conductive support structure using conventional screw and lug assemblies can, however, be quite tedious and labor-intensive (especially when the attachment location is not readily accessible). Furthermore, the presence of a lead wire can be bothersome since it is typically hidden by the mounting structures associated with the electrical component being grounded. As a result, the electrical component sometimes is not securely mounted to the support structure.
Another problem associated with mounting and grounding of electrical components to an electrically conducting support structure is that the mounting block of the electrical component (which is typically formed of a molded plastics material so as to be electrically insulating) sometimes cracks or is abraded in the vicinity of its mounting hole due to the force associated with tightening of the mounting screw used to attach the mounting block to the support structure. To overcome this problem, mounting blocks of electrical components have been provided with insert injection-molded reinforcement rings embedded in the plastics material around the individual mounting holes. However, the costs of insert injection-molded parts are typically quite high and therefore sometimes cost-prohibitive.
A relatively more affordable proposal to reinforce the mounting hole of a mounting block associated with an electrical component is to either press-fit or loosely fit a separate reinforcing ring into the individual mounting holes. However, in the case of press-fit reinforcing rings, a press-fitting tool is typically required thereby increasing both labor and equipment costs. On the other hand, in the case of a loose fit reinforcing ring, the reinforcing ring has a tendency to fall out of the mounting hole during assembly and/or mounting of the mounting block to the underlying support structure.
What has been needed in the art, therefore, is a mounting system for electrical components which not only effects secure mounting of the electrical component's mounting block to an electrically conducting painted support member, but also effects reliable grounding of the electrical component. It is towards attaining such an electrical mounting and grounding connector that the present invention is directed.
Broadly, the present invention relates to a combined mounting and grounding connector for electrical components whereby mounting of an electrically insulated mounting block of the electrical component may be reliably attached to an electrically conductive painted surface of an underlying support structure (e.g., a portion of an automobile's body) and grounding of the electrical component is achieved. In this regard, the connectors of the present invention include a bent bus bar having a lower leg section which is disposed parallel to the central axis of the mounting hole, and an upper leg section which is tightly sandwiched between the insulating body member of the electrical component and the painted surface of the electrically conducting support member.
Significantly, a terminal end portion of the bent bus bar protrudes from the electrical component's mounting block in opposition to the mounting screw used to attach the mounting block to the support structure so that the protruding terminal end portion first contacts an underneath surface of the mounting screw head when the latter is threaded into the support structure through the mounting hole in the mounting block. As a result, the bus bar bears a substantial amount of the force exerted by the mounting screw thereby minimizing the force exerted by the mounting screw that is borne by the mounting block. Thus, the risk of breakage of the mounting block in the vicinity of the mounting hole due to excessive force exerted by the mounting screw is significantly minimized (if not eliminated entirely). At the same time, electrical grounding is achieved through the mounting screw due to the electrical communication it establishes between the bent bus bar and the underlying electrically conductive painted support member.
Reinforcement of the mounting hole of the mounting block is provided according to the present invention by means of a reinforcement ring which is insertably received within the mounting hole and thus surrounds the shank of the mounting screw. Structures are provided to retain the reinforcement ring positionally within the mounting hole so that it does not fall out of the mounting hole during attachment of the connector to the underlying support structure.
For example, the reinforcement ring according to this invention may be frictionally retained within the mounting hole by providing an arcuate relief adjacent to the mounting hole which establishes a resilient web having a cam surface protruding into the mounting hole. Thus, when the reinforcement ring is inserted into the mounting hole, it will bear against the cam surface which causes the web to be resiliently radially displaced. The inherent resiliency of the web will therefore exert a responsive radially inward force against the reinforcement ring which frictionally retains the reinforcement ring within the mounting hole.
Alternatively, the terminal end portion of the bus bar may itself be bent inwardly (i.e., relative to the mounting hole) to an extent whereby it does not interfere with the shank of the mounting screw, but yet provides a positional stop against which an edge of the retaining ring will seat. As a result, the retaining ring will be positionally restrained by means of the inwardly bent terminal end portion. Furthermore, the lower leg of the bent bus bar may be angled inwardly relative to the mounting hole so that it forms a leaf spring which exerts a bias force against an exterior surface of the reinforcement ring thereby frictionally retaining the ring within the mounting hole.
Further aspects and advantages of this invention will become more clear after careful consideration is given to the detailed description of the preferred exemplary embodiments thereof which follow.